Theoretical Studies on the Potential Energy Surfaces of SO2: Electronic States for Photodissociation from the \ ildeC1B2 State

The potential energy surfaces of electronically excited states of SO2 have been investigated with ab initio molecular orbital method: Especially, the two-dimensional potential energy surface for the \ ildeC1B2 (21A′) state as a function of both the bond angle and bond distance has been carefully analyzed, including the spin-orbit interaction. Energetically, 23A′ (13A1 in C2v) was found to be the most grobable state which concerns the reaction mechanism for the photodissociation pathway from the \ ildeC state (SO2 (\ ildeC1B2)→SO(3∑−)+O(3P)); however, other pathway may also be possible to go over the avoided crossing on a singlet potential surface.